Memcached is a distributed in-memory object caching system designed to accelerate applications by reducing repeated database queries and other expensive operations. It stores frequently accessed information in RAM, allowing applications to retrieve previously calculated results without repeating the original work.
The software provides a straightforward key-value interface that can be used by applications written in many programming languages. Rather than acting as a conventional database, Memcached functions as a temporary cache where entries may expire or be evicted when memory becomes scarce.
Its architecture is intentionally simple. Applications decide which information should be cached, while Memcached handles storage, retrieval and memory management. Multiple servers can be combined into larger caching systems, making it particularly useful for busy websites and distributed applications.
This is free and open source software.
Key Features
- In-memory key-value caching – stores frequently accessed data in RAM for low-latency retrieval.
- Distributed caching – spreads cached objects across multiple servers using client-side key distribution.
- Configurable expiration – associates cached objects with expiration times.
- Automatic eviction – removes eligible objects when memory is required for new entries.
- Multithreaded operation – processes concurrent client connections using multiple worker threads.
- Non-blocking networking – uses event-driven I/O to handle network activity efficiently.
- Atomic operations – supports counters, compare-and-swap operations and other data manipulation commands.
- Meta protocol – provides advanced cache operations and controls for managing object freshness and concurrency.
- Built-in proxy – routes requests to backend Memcached servers using configurable pools and routing policies.
- External storage – optionally stores large object data on flash storage while retaining cache management information in memory.
- SASL authentication – supports authentication where enabled and configured.
- Statistics – exposes information about cache hits, misses, memory usage and server operations.
- Client library ecosystem – integrates with applications through language-specific Memcached clients.
Website: memcached.org
Support:
Developer: Brad Fitzpatrick and contributors
License: BSD 3-Clause ‘New’ or ‘Revised’ License
memcached is written in C. Learn C with our recommended free books and free tutorials.
Related Software
| Caching Systems | |
|---|---|
| Memcached | High-performance distributed memory object caching system |
| Redis | Persistent key-value database with network interface |
| Hazelcast | Distributed in-memory data store and computation platform |
| Apache Ignite | Distributed database, caching and processing platform |
| Ehcache | Standards based pure Java in-process cache |
| Java Caching System | Distributed caching system written in Java |
| Couchbase | Distributed key-value database management system |
| Apache Geode | Distributed, in-memory data management platform |
| yrmcds | LRU cache library and key-value server |
| Cachelot | Memory object caching system with master/slave replication |
| Infinispan | Distributed, in-memory database and data grid |
Read our verdict in the software roundup.
| Web Caches | |
|---|---|
| Vinyl | Web accelerator written with performance and flexibility in mind |
| HAProxy | High availability load balancer and proxy server |
| nginx | Very powerful and efficient web server and reverse proxy |
| Traffic Server | High-performance building block for cloud services |
| Squid | High-performance proxy caching server and web cache daemon |
| Envoy | High performance edge and service proxy |
| Apache APISIX | Dynamic API gateway with load balancing and traffic management |
| Apache | Hugely popular web server with caching modules |
| Souin | HTTP cache system |
Read our verdict in the software roundup.
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